summaryrefslogtreecommitdiff
path: root/framework/Collections/TStack.php
blob: de78527e216cb100259b76578129e012ea5f3386 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
<?php
/**
 * TStack, TStackIterator classes
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link https://github.com/pradosoft/prado
 * @copyright Copyright &copy; 2005-2015 The PRADO Group
 * @license https://github.com/pradosoft/prado/blob/master/COPYRIGHT
 * @package System.Collections
 */

/**
 * TStack class
 *
 * TStack implements a stack.
 *
 * The typical stack operations are implemented, which include
 * {@link push()}, {@link pop()} and {@link peek()}. In addition,
 * {@link contains()} can be used to check if an item is contained
 * in the stack. To obtain the number of the items in the stack,
 * check the {@link getCount Count} property.
 *
 * Items in the stack may be traversed using foreach as follows,
 * <code>
 * foreach($stack as $item) ...
 * </code>
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Collections
 * @since 3.0
 */
class TStack extends TComponent implements IteratorAggregate,Countable
{
	/**
	 * internal data storage
	 * @var array
	 */
	private $_d=array();
	/**
	 * number of items
	 * @var integer
	 */
	private $_c=0;

	/**
	 * Constructor.
	 * Initializes the stack with an array or an iterable object.
	 * @param array|Iterator the initial data. Default is null, meaning no initialization.
	 * @throws TInvalidDataTypeException If data is not null and neither an array nor an iterator.
	 */
	public function __construct($data=null)
	{
		if($data!==null)
			$this->copyFrom($data);
	}

	/**
	 * @return array the list of items in stack
	 */
	public function toArray()
	{
		return $this->_d;
	}

	/**
	 * Copies iterable data into the stack.
	 * Note, existing data in the list will be cleared first.
	 * @param mixed the data to be copied from, must be an array or object implementing Traversable
	 * @throws TInvalidDataTypeException If data is neither an array nor a Traversable.
	 */
	public function copyFrom($data)
	{
		if(is_array($data) || ($data instanceof Traversable))
		{
			$this->clear();
			foreach($data as $item)
			{
				$this->_d[]=$item;
				++$this->_c;
			}
		}
		else if($data!==null)
			throw new TInvalidDataTypeException('stack_data_not_iterable');
	}

	/**
	 * Removes all items in the stack.
	 */
	public function clear()
	{
		$this->_c=0;
		$this->_d=array();
	}

	/**
	 * @param mixed the item
	 * @return boolean whether the stack contains the item
	 */
	public function contains($item)
	{
		return array_search($item,$this->_d,true)!==false;
	}

	/**
	 * Returns the item at the top of the stack.
	 * Unlike {@link pop()}, this method does not remove the item from the stack.
	 * @return mixed item at the top of the stack
	 * @throws TInvalidOperationException if the stack is empty
	 */
	public function peek()
	{
		if($this->_c===0)
			throw new TInvalidOperationException('stack_empty');
		else
			return $this->_d[$this->_c-1];
	}

	/**
	 * Pops up the item at the top of the stack.
	 * @return mixed the item at the top of the stack
	 * @throws TInvalidOperationException if the stack is empty
	 */
	public function pop()
	{
		if($this->_c===0)
			throw new TInvalidOperationException('stack_empty');
		else
		{
			--$this->_c;
			return array_pop($this->_d);
		}
	}

	/**
	 * Pushes an item into the stack.
	 * @param mixed the item to be pushed into the stack
	 */
	public function push($item)
	{
		++$this->_c;
		$this->_d[] = $item;
	}

	/**
	 * Returns an iterator for traversing the items in the stack.
	 * This method is required by the interface IteratorAggregate.
	 * @return Iterator an iterator for traversing the items in the stack.
	 */
	public function getIterator()
	{
		return new ArrayIterator( $this->_d );
	}

	/**
	 * @return integer the number of items in the stack
	 */
	public function getCount()
	{
		return $this->_c;
	}

	/**
	 * Returns the number of items in the stack.
	 * This method is required by Countable interface.
	 * @return integer number of items in the stack.
	 */
	public function count()
	{
		return $this->getCount();
	}
}

/**
 * TStackIterator class
 *
 * TStackIterator implements Iterator interface.
 *
 * TStackIterator is used by TStack. It allows TStack to return a new iterator
 * for traversing the items in the list.
 *
 * @deprecated Issue 264 : ArrayIterator should be used instead
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package System.Collections
 * @since 3.0
 */
class TStackIterator implements Iterator
{
	/**
	 * @var array the data to be iterated through
	 */
	private $_d;
	/**
	 * @var integer index of the current item
	 */
	private $_i;
	/**
	 * @var integer count of the data items
	 */
	private $_c;

	/**
	 * Constructor.
	 * @param array the data to be iterated through
	 */
	public function __construct(&$data)
	{
		$this->_d=&$data;
		$this->_i=0;
		$this->_c=count($this->_d);
	}

	/**
	 * Rewinds internal array pointer.
	 * This method is required by the interface Iterator.
	 */
	public function rewind()
	{
		$this->_i=0;
	}

	/**
	 * Returns the key of the current array item.
	 * This method is required by the interface Iterator.
	 * @return integer the key of the current array item
	 */
	public function key()
	{
		return $this->_i;
	}

	/**
	 * Returns the current array item.
	 * This method is required by the interface Iterator.
	 * @return mixed the current array item
	 */
	public function current()
	{
		return $this->_d[$this->_i];
	}

	/**
	 * Moves the internal pointer to the next array item.
	 * This method is required by the interface Iterator.
	 */
	public function next()
	{
		$this->_i++;
	}

	/**
	 * Returns whether there is an item at current position.
	 * This method is required by the interface Iterator.
	 * @return boolean
	 */
	public function valid()
	{
		return $this->_i<$this->_c;
	}
}